Tamwar suffered burns when he raced into the blaze last month, determined to save his wife Afia (Meryl Fernandes) as he thought she was inside.
Since then, Tamwar has been recovering in hospital - and an upcoming episode will see him show the scars that he now has on his back following his ordeal.
Patel told TV Times: "He doesn't want to show them to anyone and, when we do eventually see them, it won't be a sight for sore eyes."
Discussing his alter ego's current state of mind, the actor added: "He becomes more of the Tamwar we saw before [he married Afia] - the one that hardly ever smiles. He shuts himself off from everyone."
Tamwar and Afia's marriage has hit the rocks following the devastating events of Christmas, but next week's episodes see Zainab (Nina Wadia) desperately trying to reunite the pair.
EastEnders continues on Thursday at 7.30pm on BBC One.
> EastEnders' Tamwar, Afia should stay together, says Himesh Patel
> Read more EastEnders spoilers and news
Watch Tamwar's EastEnders character trail below: